Mobile apparatuses such as mobile phones have been developed to provide many functions. A user may use a mobile apparatus to access various private information. For example, the user may use a mobile phone to access bank accounts, pay bills, carry out on-line purchases, and access various password-protected websites. Personal information of these types is private and is often subject to identity theft and invasion of privacy. Thus, in recent years, privacy protection has become a focus of research and development in display technology.